Connector with a plug and a socket

ABSTRACT

The electrical connector (1) with a socket section (2) and a plug section (3) contains a clip (4) by which the pin (5) of the plug section (3) can be clamped in the axial direction and secured against unintentional withdrawal. In addition there is protection against contact with the live parts of the connector (1) which nevertheless permits the rotation of the clip (4) so that it can be closed and opened. Essentially, the plug section (2) has a sleeve (13) which surrounds the pin (5) externally and in spaced relationship to it and is rotatable in relation to the plug section (2), which sleeve (13) is of such an axial length and inner dimensions that, with the pin (5) inserted into the clip (4), the sleeve (13) is axially movably pushed in an axial direction onto the component serving to rotate the conical section (6) of the clip (4) and at the same time is coupled thereto in the direction of rotation. Rotating the sleeve (13) when the electrical connector is assembled can thus close the clip and contra-rotating it opens said clip, the conical section (6) then moving axially in relation to the sleeve but being also driven in the direction of rotation. At the same time, the sleeve (13) protects the pin (5) against undesired contact even when the connector (1) is disassembled.

BACKGROUND OF THE INVENTION

The invention relates to an electrical connector with a plug and asocket, whereby the socket has a clamping device for fixing a pin of theplug, the clamping device consisting of a clip and a conical sectionform-lockingly interconnected by means of a threaded joint and thefixation of the plug pin in the clamping device being constituted by therelative movement of clip and conical section to each other by means ofthe threaded joint.

A connector of such a character is known from German Utility Model No. 1738 657. The retention force between plug and socket can besignificantly improved by the clamping device. At the same time, plugpins of different sizes can also be held with high axial tensilestrength.

A drawback presenting itself is, however, that the plug pin can becontacted when plug and socket are not intermated, or not fully so, andas a result for example an electrostatic charging by the contactingperson can lead to an undesired current flow. This is highlydetrimental, particularly if and when the lead issuing from theconnector belongs to an electromedical device and is conducted, forinstance, to a patient's heart. Therefore the electrical connectoraccording to German Utility Model No. 1 738 657 is not suited for suchuse.

To be sure, it is already also known to provide connectors protectedagainst accidental contact, however, with these the plug is theninsufficiently secured against inadvertent withdrawal, which would beespecially disadvantageous in case of use on an electomedical device.

In various fields of technology and particularly in medical technology,to which mention was already made, it is often necessary to have leadsand particularly electrical connectors which are protected againstaccidental contact, but are also adequately protected againstinadvertent disconnection.

SUMMARY OF THE INVENTION

The object underlying the invention is therefore to provide anelectrical connector of the type set forth at the outset, preserving theadvantages of a clamping device in the socket and neverthelesspermitting accidental-contact protection of the plug pin, although theplug pin is to be inserted into the clamping device and clip thereof andit is then to be possible to close the latter by the screw movement.

To accomplish this object, the electrical connector mentioned at theoutset is characterized in that the plug has a rotatably mounted sleevewhich surrounds the plug pin externally and in spaced relationship to itand is of an axial length and internal dimensions adapted to the conicalsection of the clamping device, whereby in the assembled condition saidsleeve is axially movably pushed onto the conical section and at thesame time is form-lockingly coupled to the conical section in thedirection of rotation.

By virtue of this sleeve, the plug pin is hence shielded at leastlaterally, thus even if the plug is withdrawn from the socket the pincannot be inadvertently contacted when taking hold of the plug.Nevertheless, after the plug pin has been inserted into the clip, it ispossible to rotate the conical section, although strictly speaking thisis prevented by the sleeve. This contradiction is eliminated accordingto the invention in that the sleeve is rotatable and is directly orindirectly coupled to the conical section in the direction of rotation,so that the sleeve can be rotated for rotating the conical section andfor closing the clip. Since, however, the sleeve itself remains axiallymovable in relation to the conical section, the axial movement relativeto the sleeve brought about by rotating the conical section can takeplace unproblematically. As this is taking place, the plug pin itselfretains its inserted position unchanged and, by turning the sleeverotatable relative thereto, is clamped by the clip. Consequently thesleeve has a dual function by protecting the plug pin against accidentalcontact and simultaneously, through its rotation, serving to close theclip of the clamping device.

It is particularly suitable if the rotatable sleeve is captivated on theplug. Hence a rotary coupling between sleeve and plug is suitable whichis nondetachable or is not readily detachable. Neither can the originalaccidental-contact protection be inadvertently removed. Consequently,also in the coupled condition, that is when plug and socket areassembled, this sleeve cannot be removed and it then still retains itsfunction as accidental-contact protection in this position.

It is especially advantageous if the rotatable sleeve is longer in theaxial direction than the pin of the plug and projects beyond the pin inthe axial direction. By this means the accidental-contact protection isenhanced as compared with an arrangement in which sleeve and plug pinend at about the same level.

Further improved accidental-contact protection, also when the connectoris in a detached condition, can be achieved by the rotatable sleeveprojecting beyond the plug pin so far that the plug pin is unreachablefor a finger. This can be promoted by also selecting the diameter of theopen free end of the sleeve to be appropriately small.

The compressible parts of the clip, and the pin, are made of metal andthe conical section exhibiting the cone for compressing the clip caninsulate the clip at least externally, in particular can be made ofplastic. Consequently the socket is also protected against accidentalcontact to a very large extent, but nevertheless permits good contactingwithin the plug arrangement.

The conical section can have--on a suitable sleeve or the like--aninternal thread fitting on an external thread of the clip, and the innercone of the conical section and the outer cone of the clip can bearranged axially adjacent to the threaded area; this threaded part canbe externally coated with the insulation, particularly of plastic,whereby this plastic coating can be of sleeve-like configuration and atthe end opposite the insertion end can project axially beyond thethreaded area by at least the distance taken for unscrewing the fitting.Therefore accidental-contact protection is preserved even when the clipis open, when possibly the plug pin is still inserted in it. Hence, alsowhen the connector is assembled, it is prevented that accidental contactbe made with metallic, electroconductive parts connected to theelectrical lead to e.g. the heart.

The insulation of the conical section can overlie and cover its frontface, further enhancing the accidental-contact protection. It is truethat this front face is situated inside the sleeve during insertion ofthe plug pin or also during withdrawal, however it cannot be ruled outthat the plug is connected to a lead conducted to a sensitive part ororgan, so that there as well the contact and transfer for instance of anelectrostatic charge is to be prevented.

Further improvement, particularly in the accidental-contact protection,can be achieved by the rotatable sleeve being made of or covered byinsulating material, particularly plastic. Therefore, even in adverseconditions, no electric current or voltage can reach the plug pinor--when the connector is assembled--the socket and its electriccontacts, hence the clip.

The rotatable sleeve can be externally profiled, for instance knurled orroughened. This renders it simpler to rotate for closing the clip andhigher torque can be transferred, hence clamping force of commensuratemagnitude can be attained, even if the outer diameter of thesleeve--also for improving the accidental-contact protection from itsfront face--is selected to be relatively small.

A simple solution in structural terms is obtained if the rotatablesleeve is slipped onto a connecting piece of the plug--through which theplug pin emerges--and is fixed in the axial direction by a snapconnection or by an element engaging simultaneously with the connectingpiece and with the sleeve. A snap connection has the advantage ofpermitting very simple assembly. A locking element for axial fixation,engaging simultaneously with the connecting piece and with the sleeve,permits that the sleeve be disassembled and replaced if necessary,should the sleeve become damaged in use with the result that it might nolonger be capable of performing its functions, particularly theaccidental-contact protection.

The connecting piece, which belongs to the plug and rotatably mounts therotatable sleeve, can have an annular groove and a cross pin can bearranged tangentially to this groove or base thereof, the cross sectionof said pin in any case engaging with the groove. In addition, the crosspin traverses the rotatable sleeve transversely of the centre axis ofthe sleeve and eccentrically thereto. Therefore the sleeve can berotated together with the cross pin, because the latter can then bemoved in and at the periphery of the annular groove, while being inengagement therewith. In case of need, however, this cross pin can bepushed in its longitudinal direction back out of a corresponding bore inthe sleeve or--if it is a threaded pin--can be unscrewed. Furthermore, arotary coupling establishing axial fixation between sleeve and plug isnaturally also possible with the aid of spring rings or the like.

To be sure, the rotatable sleeve could have an inside profiling which iscircular in cross section and co-operates frictionally with thescrewable conical section. However, it is especially suitable if theinside profiling of the rotatable sleeve and the outside profiling ofthe rotatable conical section, or more specifically its insulation, arein each case a tallying polygon. Therefore the rotary movement at thesleeve can be transferred through a form fit to the conical sectionwhich then can nevertheless perform the axial movement relative to thesleeve, as ensues during the screw action. At the same time, slippingthe sleeve onto this conical section becomes considerably simpler thanif an inwardly directed projection inside the sleeve would have to beinserted into a corresponding external groove of the conical section--orvice versa.

Particularly when the above-described features and measures are combinedsingly or severally, a clip connector protected against accidentalcontact ensues, including a clip and a specially shaped screw-on cap, ormore specifically a specially shaped screwable conical section, withwhich adequate protection against accidental contact from the top andfrom the sides is ensured and which is also shaped in such a way as tobe able to enter into a mechanical form fit with the speciallyconfigured plug in the direction of rotation, so as to be capable ofbeing screwed with the plug, or more specifically with the appertainingsleeve, but simultaneously permitting the relative axial movementnecessary for this purpose. This sleeve serving for screw action iscaptive and for its part extends beyond the plug pin so far as tolikewise constitute accidental-contact protection. Both in the detachedand in the assembled position, the accidental-contact protectionnecessary in many instances when the connector is detached is achieved.Nevertheless, the advantage of a clip with correspondingly goodcontacting and, above all, firm coupling in the axial direction, as wellas adaptation to plug pins varying in thickness is attained.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the invention will be described in greaterdetail below with reference to the drawings in which, in schematizedform,

FIG. 1 depicts, partly in longitudinal section, a connector in thewithdrawn position, in which a socket with a clip is fixed to a housingwall and has a connection to a power source, while the complementaryplug presenting a pin is arranged on a lead to a current consumer, forinstance to a patient's heart,

FIG. 2 is the connector of FIG. 1 after assembly and after the pin hasbeen clamped in the clip, on an enlarged scale

FIG. 3 is a longitudinal section through the socket with its front viewseen in the direction of the arrow in the same Figure,

FIG. 4 is a longitudinal section through the clip of the socket with theclamping jaws, a slot therebetween and the conical ends of this clip aswell as an external thread,

FIG. 5 is a longitudinal section through a conical section having aninner cone complementary to the front conical ends of the clip, wherebyadjacent to this inner cone is an internal thread which fits on theexternal thread of the threaded body of the clip and, when this conicalsection is screwed home, results in an axial movement and thus tocompression of the clip,

FIG. 6 is a longitudinal section through the plug, shown on a largerscale than in FIGS. 1 and 2, with the rotary mount of a sleeve whichserves as accidental-contact protection for the plug pin and alsoaxially projects beyond the latter, and

FIG. 7 is the front view of the plug seen from the open end of therotatable sleeve, showing the octagonal inside profiling of the sleevecorresponding in shape and size to the octagonal outside profiling ofthe screwable conical section according to FIG. 3, hence belonging tocoupling effective in the direction of rotation between sleeve andconical section.

DETAILED DESCRIPTION OF THE INVENTION

An electrical connector, generally designated 1, has in the customaryfashion a plug 3 and a socket 2 whereby, according to FIG. 1 andparticularly according to FIGS. 3 and 4, the socket 2 contains a clip 4or a similar clamping device into which a pin 5--the single pin 5--ofthe plug 3 is insertable. By means of a screw movement of a conicalsection 6, which according to FIG. 5 has an inner cone 7, the clip 4provided with axial slots 8 can be compressed in the customary fashion,the clip having at its free ends a complementary cone 9 to the innercone 7. It is evident that by screwing the conical section 6 to theright so as to depart from the position depicted in FIG. 3, the axialslots 8 and thereby the clip 4 is compressed, because the inner cone 7compresses the complementary cone 9 accordingly. If then according toFIG. 2 the plug pin 5 is situated in the clip 4, it is fixed withcorrespondingly good clamping force, avoiding unintentional detachmentof the connection as a whole.

FIGS. 3 and 4 show an external thread 10 on the clip 4 and fitting on itan internal thread 11 on the conical section 6, adjacent to the innercone 7. As a consequence, the already mentioned compression of the clip4 by a screw movement of the conical section 6 is enabled, so that thepreviously inserted pin 5 of the plug 3 is fixed and located in positionin the clip 4 of the socket 2. The thread can be tightened so firmly soas practically preclude unintentional withdrawal of the plug pin 5. Thefront view according to FIG. 3 shows that the clip 4 has four clampingelements or clamping fingers 12 and accordingly also four axial slots 8.

Particularly in FIG. 6, but also in FIG. 1 one can see that the plug 3carries a rotatably mounted, generally cup-shaped sleeve 13 surroundingthe plug pin 5 externally and in spaced relationship to it. Further, onecan see that the sleeve 13 is of such an axial length and internaldimensions that according to FIG. 2, when the plug pin 5 is insertedinto the clip 4, the sleeve 13 is axially movably pushed in an axialdirection onto the component serving to rotate the conical section 6 ofthe clip 4 and at the same time is coupled thereto in the direction ofrotation.

Therefore it is possible to insert the plug pin 5 into the centralopening 14 of the clip 4, between the clamping fingers 12 of the clip 4,and thereby at the same time to push the sleeve 13 onto the outside ofthe conical section 6 and to couple it to this conical section 6 in thedirection of rotation. As a result, despite the sleeve 13 making theplug pin 5 inaccessible from the side, the screw movement at the clip 4can be carried out by now rotating the sleeve 13. The sleeve 13 thendrives the conical section 6 so that the latter is screwed further andfurther onto the external thread 10, such bringing about the desiredcompression of the clamping fingers 12 of the clip 4 and thereby thefixation of the plug pin 5.

FIG. 6 illustrates that the sleeve 13 protects the plug pin 5 againstaccidental contact, particularly from the side. This protection is alsopreserved in the closed position of the connector 1 according to FIG. 2,because the rotatable sleeve 13 is captivated on the plug section 3, aswill be explained below.

FIGS. 1 and 6 also illustrate that the rotatable sleeve 13 is longer inthe axial direction than the plug pin 5 and projects axially beyond it.Accidental contact of the plug pin 5 is therefore impeded further. Thesleeve 13 can project beyond the plug pin 5 so far that the plug pin 5is unreachable for a finger. Thus good protection against accidentalcontact ensues even when the plug 3 is detached, this being of greatsignificance and advantage if and when, for instance, the lead 14apresenting the plug 3 is conducted to a patient's heart. Namely, it isruled out that electrostatic charging by the user of the plug 3can--inadvertently--send its charge via the plug pin 5 and lead 14a tosuch a patient.

The compressible components of the clip 4, that is its clamping fingers12, and the plug pin 5 are made of metal, for example brass, for goodcontacting. The conical section 6 exhibiting the inner cone 7 forcompressing the clip 4 is configured in such a way as to externallyinsulate the clip 4. By way of example, the conical section 6 could bemade of plastic, however according to FIG. 5 it is proposed that it isprovided with a sleeve-like plastic coat 15. Therefore the area of theinner cone 7 and internal thread 11 is externally coated with theplastic insulation, whereby according to FIGS. 1 to 3 and 5 at the endopposite the insertion end this plastic coat 15 projects axially beyondthe thread area by at least the distance taken for unscrewing thefitting. It is apparent that the plastic coat 15 still engages over thearea of the thread 10 even in the open condition (FIG. 1), so thatlateral access to the thread 10 is also prevented in this position.Since the area adjoining this thread 10 is again insulated by a plasticcoat, the entire socket 2 is externally insulated and hasaccidental-contact protection, so that there as well the contact by aperson does not lead to undesired transfer of current or voltage, aswould be adverse particularly if and when the plug pin 5 is in theposition of use.

According to FIG. 5, the insulation 15 of the conical section 6 alsooverlies its front face 16, so that even under adverse conditions acontact of electroconductive parts of the connector 1 appearsimpossible.

The rotatable sleeve 13 of the plug 3 can for its part be made of orcoated by insulating material, plastic for example. However, this is notabsolutely necessary if, as described, the conical section 6 and alsothe other parts of the plug-in component are insulated toward theoutside or have an insulating coat 15.

In FIG. 6 it is indicated that the rotatable sleeve 13 can be externallyprofiled, for example knurled or roughened. Since the clamping force forfixing the plug pin 5 in the clip 4 is to be generated at this sleeve 13by rotating it, such a configuration is an aid. Clamping forces ofsuitable magnitude can be generated even if the outer circumference ordiameter of the sleeve 13--for improvement of the accidental-contactprotection from its open end--is selected to be relatively small.

According to FIG. 6, the rotatable sleeve 13 is slipped or pushed onto aconnecting piece 17 of the plug 3 and can be captivated there by a snapconnection. In the exemplary embodiment, however, the sleeve 13 isaxially fixed by an element, namely a cross pin 18, simultaneouslyengaging with the connecting piece 17 and the sleeve 13. This isrealized by the connecting piece 17 which belongs to the plug 3 androtatably mounts the rotatable sleeve 13 having an annular groove 19 andby the cross pin 18 being arranged approximately tangentially to theannular groove 19 or base thereof, and having its cross section partlyin engagement therewith, in the exemplary embodiment by about half, andby the cross pin also traversing the rotatable sleeve 13 crosswise ofits centre axis and eccentrically thereto. By reference to FIG. 6 it isapparent that this permits a rotation of the sleeve 13, the sleeve 13then being rotated together with the cross pin 18 because the cross pin18 can move along the annular groove 19. An axial detaching movement ofthe sleeve 13 off the connecting piece 17 is however prevented by thecross pin 18 engaging with the annular groove 19.

In regarding the front view of the conical section 6 with its coat 15 inFIG. 3 together with the sleeve 13 from its open side in FIG. 7, itbecomes clear that the inside profiling of the rotatable sleeve 13 andthe outside profiling of the rotatable conical section 6 or morespecifically the coat 15 thereof correspond in each case to a polygon,whereby in the exemplary embodiment an octagon is provided. Such permitseasy assembly without complicated interassociation of parts andnevertheless in the direction of rotation produces a firm, butdetachable coupling, which also permits the necessary relative movementbetween sleeve 13 and conical section 6 during the screw action.

At the same time, the projecting length 20 of the coat 15 departs fromthe detached position depicted in FIG. 1 and 3 and is pushed furtherover a base 21 of the external thread 10. In order that also in the openposition accidental contact of the metallic thread 10 or its base 21 isprevented there, this area or base 21--not shielded by the conicalsection 6, or more specifically by its insulating coat 15 when the clipis in the open position with inserted plug pin 5--is likewise externallyinsulated by a generally cup-shaped insulating body 22. The latter alsoprovides insulation with respect to a housing wall 23 to which thesocket 2 is attached in this exemplary embodiment.

We claim:
 1. An electrical connector (1) with a plug (3) and a socket(2), whereby the socket (2) has a clamping device for fixing a pin (5)of the plug (3), the clamping device consisting of a clip (4) and aconical section (6) form-lockingly interconnected by means of a threadedjoint and the fixation of the plug pin (5) in the clamping device beingconstituted by the relative movement of clip (4) and conical section (6)to each other by means of the threaded joint, characterized in that theplug (3) has a rotatably mounted sleeve (13) which surrounds the plugpin (5) externally and in spaced relationship to it and is of an axiallength and internal dimensions adapted to the conical section (6) of theclamping device, whereby in the assembled condition said sleeve (13) isaxially movably pushed onto the conical section (6) and at the same timeis form-lockingly coupled to the conical section (6) in the direction ofrotation.
 2. An electrical connector as claimed in claim 1,characterized in that the rotatable sleeve (13) is captivated on theplug (3).
 3. An electrical connector as claimed in claim 1,characterized in that the rotatable sleeve (13) is longer in the axialdirection than the pin (5) of the plug (3) and projects beyond said pinin the axial direction.
 4. An electrical connector as claim 1,characterized in that the sleeve (13) projects axially beyond the plugpin (5) so far that the plug pin (5) is unreachable for a person'sfinger.
 5. An electrical connector as claim 1, characterized in that thecompressible parts of the clip (4), and the pin (5), are made of metaland that the conical section (6) exhibiting an inner cone (7) forcompressing the clip (4) externally insulates the clip (4), inparticular is made of plastic.
 6. An electrical connector as claim 1,characterized in that the conical section (6) has an internal thread(11) fitting on an external thread (10) of the clip (4), and that theinner cone (7) of the conical section (6) and a complementary cone ofthe clip (4) are arranged axially adjacent to the threaded area, andthat said threaded part is externally coated with the insulation,particularly of plastic, whereby said plastic coating (15) is ofsleeve-like configuration and at the end opposite the insertion endprojects axially beyond the threaded area by at least the distance takenfor unscrewing the fitting.
 7. An electrical connector as claim 1,characterized in that the insulation of the conical section (6) overliesand cover its front face (16).
 8. An electrical connector as claim 1,characterized in that the rotatable sleeve (13) is made of or covered byinsulating material, particularly plastic.
 9. An electrical connector asclaim 1, characterized in that the rotatable sleeve (13) is externallyprofiled, for instance knurled or roughened.
 10. An electrical connectoras claim 1, characterized in that the rotatable sleeve (13) is slippedonto a connecting piece (17) of the plug (3) and is fixed in the axialdirection by a snap connection or by an element engaging simultaneouslywith the connecting piece (17) and with the sleeve (13).
 11. Anelectrical connector as claim 1, characterized in that a connectingpiece (17), which belongs to the plug (3) and rotatably mounts therotatable sleeve (13), has an annular groove (19) and that a cross pin(18) is arranged tangentially to said groove (19) or base thereof, thecross section of said pin partly engaging with the groove (19), whichcross pin additionally traverses the rotatable sleeve (13) transverselyof the centre axis of the sleeve and eccentrically thereto.
 12. Anelectrical connector as claim 1, characterized in that the insideprofiling of the rotatable sleeve (13) and the outside profiling of therotatable conical section (6) correspond to a polygon.
 13. An electricalconnector as claimed in claim 1, characterized in that the externalthread (10) has a base (21) which, when the clip (4) is in the openposition with the plug pin (5) inserted therein, is shielded by aninsulating body (22).